Instrument carrier



July 5, 1938. I

C. M. POTTER INSTRUMENT CARRIER Filed Oct. 1, 1935 Fig. 5

JILVQI 'LZOJ CHARLES M. POTTER Fig.1

' Patented July 5,1938

UNITED STATES PATENT OFFICE Standard Oil Company, San Francisco, Calif.,

a corporation of Delaware I gApplication October 1, 1935, Serial No.43,078

' 6 Claims. '(01. sa-zos) This invention relates to a carrier forinstruments of the type that are sent to the bottom of deep wells forthe purpose of determining the pressure, temperature, inclination, andthe like, and more particularly relates to a free carrier that isimpelled to the bottom of the well under the action of a fluid pumpeddownwardly through a pipe, and thereafter returns by its own buoyancy,as distinguished from one which is lowered at the end of a wire or cableand is subsequently raised thereby.

In the drilling of deep wells it is the practice to use a hollow stem'ordrill pipe to support and turn the drill bit. Fluid such as water, ormud to the surface. Instruments for determining inclination. of thedrill hole, for example, are usu-" ally sent down the bore-of the drillpipe at the end of a wire or cable and, after a suitable time, withdrawnto the surface and observed. Under certain circumstances,theintroduction of such wires or cables is hazardous and objectionable.An alternative that is sometimes followed is to securethe instrument ina section of the drill pipe, immediately above the bit, which requiresremoval of the entire string of pipe before the instrument can be takenout and read.

It is an object of this invention to provide a free carrier for aninstrument which is to be sent down a well, which is adapted to bepositively carried down by the circulating fluid in the drill pipe, andwhich will be equally positively returned to the surface by virtue ofits construction and inherent buoyancy in the fluid.

Another object is to provide a carrier that will automatically beactuated when it arrives at the bottom of the drill pipe, so that itwill be in condition to return to the surface.

Another object is to provide a buoyant carrier with means for initiallyovercoming its buoyancy so that it may be sent down a drill pipe withthe circulating fluid, and thereafter be-actuated to cause it to returnto the surface of its own accord.

Another object is to provide an improved means for positioning andselectively actuating a collapsible packer on a device of this nature.

' These and other objects and advantages will be more fully apparentfromthe following description and from the accompanying drawingr whichforms a part of this specification and illustrates a preferredembodiment of this invention.

In the drawing:

the drill pipe.

Figure 2 is a horizontal sectional view on the line IIlI of Figure 1,and illustrates the arrangement of the packer skirt and expandertherefor.

Figure 3 is a vertical sectional view of a porthe packer in its closedor collapsed position.

Referring to the drawing and particularly to Figure 1, the referencenumber III represents the body of the carrier threaded at II onto themandrel I2 which carries the packer I3. Packer I3 is preferably of amolded flexible material such as vulcanized rubber andvis clampedbetween the lower end of mandrel I2 and base I4 as by the threadedconnection I5. Base I4 may tion of the carrier shown in Figure l, butwith terminate at its lower end in a spring or other shock absorbingdevice to prevent too great shock to the instrument under conditions tobe described below.

as by the hinged'brackets 2|.

Springs I9 are biased to collapse the packer I3 to the closed positionshown in Figure 3, and in order to do so must first rotate latch ring I!in a clockwise direction relative to packer I3, from the position shownin Figure 2. Conversely, if latch ring I! is rotated counterclockwisewith respect to packer I3, the. skirt of packer I3-will be expandedoutwardly to the open position shown in Figure 1.

In order to secure latch ring Ilin the open position of Figure 1,mandrel I2 is provided with a slot 22 in which is pivoted a pawl 23, theouter notch 24 in ring I'l.

held in the upper position shown as-by spring II.

-end of which is adapted to be received in a A cover plate 25 may besecured over slot 22 and pawl 23 as by a screw 26. The inner end ofpawl23 extends into a bore 21 in mandrel I2, 111 which bore the stem 28 ofan inertia member 29 is adapted to move. The main body of inertia member29 is received in a bore 30 in the carrier body III and is normally inFigure An instrument carrying section .32 is secured to the top of bodywas by the threaded connection 33, and is provided with a chamber 34into which any suitable surveying instrument may placed. A shortthreaded stub 35 is pref= erably provided. on top of section 32 so thata fishing tool may be used to recover the carrier should it become stuckin theedrill pipe.

The body l0, mandrel I 2, base I and instrument section .32 arepreferably made of a very light metal alloy such as an aluminum or amagnesium alloy, in order that the whole assembly will beibuoyant in themud or circulating fluid To this end, the base l4 may be hollow for aortion of its length.

In operation, the skirt of packer I2; is pulled outwardly until latchring I! is turned counterclockwise to the position shown in Figure 1,

whereupon the outer end of pawl 23 will engage notch 24 in ring I! andhold it in that position, with the packer l3 expanded. The carrier, withthe instrument in place in chamber 34, is then placed in the drill pipe36in the usual manner and pumped down with the circulating fluid, theexpanded packer serving to assist in the operation by sealing the spacebetween the drill pipe 36 and the carrier body.

As soon as the carrier strikes the bottom of the drill pipe, which isciosed by the drill bit, except for one or two small fluidpassages, theinertia member 29 will move downwardly relative to the carrier body sothat stem 28 will strike the inner end of pawl 23. This will releasering I! so that springs l9 will collapse the packer l3 to the positionshown in Figure 3. Continued pumping of circulationfiuid will assist therim-of the packer l3 to fold downwardly, as shown, and will also serveto hold the carrier at the bottom of the drill pipe until the normaloperating or recording period of the instrument has elapsed. As .soon asthe pumping is stopped, the carrier, by virtue of its positive buoyancy,will rise to the surface and can then be removed from the drill pipe inthenormal manner.

Although a specific construction embodying this invention has beendescribed and illustrated, it

/ is to be understood that the invention is not limited to that specificdevice, and all such'modifications and changes as come within the scopeof the appended claims are embraced thereby.

I claim:

An instrument carrier adapted to be pumped down a drill pipe with acirculatingfluid, comprising a buoyant body, a flexible packer securedto said body,'a rotatable ring on said body, spring means connectingsaid packer withsaid ring, a latch for said ring to hold said packer inexpanded position and means associated with said body and adapted torelease said latching means to retract said packer when said bodyreaches the bottom of said pipe. 1

2. An instrument :carrier according to claim 1 in which said last namedmeans comprises an inertia member carried by said body and movable withrespect thereto, and said latching means comprises a pawl adapted to becontacted bysaid member when said body reaches the bottom of said pipe.i V Y 3. An instrument carrier adapted to be pumped down a drill pipewith a circulating fluid, comprising a buoyant body, a flexible packersecured to. .said body, a rotatable ring on said body, spring meansconnecting said packer with said ring and adapted to urge said packer toa collapsed position, an inertia member slidably mounted in said body,and a pawl for holding said ring in position to expand said packer, saidmember being normally restrained from contacting said pawl but adaptedto release it when said body strikes the 1 bottom of said pipe.

4. An instrumentcarrier adapted to be pumped down a drill pipe with acirculating fluid, comprising a buoyant body, a flexible extensiblepacker carried by and surrounding said body, a movable ring on saidbody, means connecting said:

packer with said ring, and releasable latching means in said body forholding said ring in a position to maintain said packer in its extendedposition, said latching means comprising an inertia member carried bysaid body and movable with respect thereto, said inertia member soconstructed and arranged as to actuate said latching means when saidbody reaches the bottom of said pipe.

5 An instrument carrier according to claim 4 in which said movable ringis rotatable to expand said packer and to contract the same.

6. An instrument carrier adapted to be pumped down a drill pipe with acirculating fluid, comprising a. buoyant body, a flexible extensible

